Wednesday, March 26, 2014

Pycnogenol-Based Antioxidant Supplement Lactaway(TM) Boosts Resistance Training Performance, But Reduces GH Release by 60% - Is the Growth Hormone "Loss" Relevant?

Performance ↑, Growth Hormone ↓
Alright, I know that no one actually knows how important the post-exercise increase in systemic growth hormone actually is when it comes to building muscle (there is little doubt that the local expression of splice variants is relevant). In spite of that I still feel it's still worth mentioning that a group of researchers from Australia and the United Kingdom have recently established that the provision of the antioxidant supplement Lactaway increases the muscle contractile performance "at the expense" of the post-workout growth hormone increase (Ackermann. 2014).

Why? Well those people who are most likely to spend money on expensive anti-oxidant supplements are usually also the ones who believe in the "muscle building magic" of the post-workout GH increase.
What is in this "antioxdidant" supplement? Lactaway "as in lactate away" is a, according to manufacturer claims, a "pre workout supplement (nutraceutical) that is scientifically proven to increase endurance and help with post work out recovery". Non-sponsored studies from the University of New South Wales to support this claim exist (Mach. 2010; Bentley. 2012) - in spite of the fact that the only active ingredient is the patented pine bark extract alleged NO booster and natural viagra alternative Pycegnol™.
The study had a double blind repeated measures design where the subjects, 15 healthy men (age 23 ± 4 yr: body mass 86 ± 6 kg: height 179.4 ± 6.1 cm) who had at least 2 years of prior resistance training experience, ingested either the AOX treatment (one serving of Lactaway) or a placebo version (same energy content, same basic ingredients, i.e. pineapple pulp, molasses, sodium chloride, flavour, steviol glycosides, sodium benzoate, potassium sorbate, but no pycnogenol) prior to completing the training session.

In the 48 h leading up to these sessions the subjects were instructed to refrain from intense physical exercise in order to eliminate residual fatigue. The supplements were provided using a randomized and counterbalanced design. The subjects visited the laboratory on three occasions, firstly to record their physical characteristics and determine their 3 RM BS which was used to predict 1RM strength. Their testing days looked as follows:
Learn more about the effects of testosterone, GH, IGF-1 & Co on skeletal muscle hypertrophy!
"After a brief cycling warm up, the subjects completed a warm up set consisting of 10 repetitions at 50% of the actual load to be used during the work sets. After a two min rest period the subjects performed the second warm up set at 80% of the load to be used during the work sets. After a three min rest period, subjects completed six sets, separated by 2 min rest periods. The subjects were instructed to lower the barbell under control (eccentric) and then verbally encouraged to 'drive' the barbell upwards in as short as time possible (concentric). The squat training session lasted ~18 min."
At the end of each training session, the subjects were also asked their rate of perceived exertion (RPE) using the Borg scale (Borg. 1987). Blood samples were collected and analyzed for lactate, GH and cortisol.

Lactaway does not keep the lactate away
Contrary to what you would expect it from a supplement with the name "Lactaway", the subjects in the active arm of the trial did not have lower blood lactate levels than their peers in the control arm. Moreover, "there were [...] no significant differences in RPE between the AOX and placebo conditions at any point".
Figure 1: Mean power (left; W) and velocity (right; m/s) during standardized resistance training regimen, when the trainees trained with and without the antioxidant supplement (Ackermann. 2014)
What the supplement did do - and you know that already - was to abolish the decrease in concentric  mean power that occurred from set 1 to set 6 in the control condition:
"During the placebo trial concentric mean power was significantly lower in comparison to each set in the AOX condition, with sets five and six having the greatest decrease (p < 0.05, ES’r = 0.52). Similarly average velocity during the AOX was higher compared to placebo."
With higher velocity and mean power, the accumulated power output during the AOX hyptrophy training was significantly higher (6746 ± 5.9W vs. 6493 ± 17.1W) than in the placebo trial. In view of the previously reported association between post-workout growth hormone release and  total work, it's thus not exactly logical that the growth hormone response in the AOX trial was reduced by 59% (6.65ng/ml vs. 16.08ng/ml) compared to the placebo trials (see Figure 2).

These  differences stand in contrast to increase in cortisol, which was identical in both the AOX and placebo trials and remained significantly elevated 20 min post exercise for both treatments (p< 0.05).
Figure 2: GH response (ng/ml) of previously trained men to a standardized resistance training regimen with (AOX) and without (PLA) pre-workout antioxidant (pycnogenol) supplementation (Ackermann. 2014).
Short term performance gains, but impaired long(er) term adaptation? If we put faith into the often-cited results of West's and Phillips' 2012 study of the "Associations of exercise-induced hormone profiles and gains in strength and hypertrophy in a large cohort after weight training", the reduced GH release would in fact imply that the subjects "on" Lactaway would see lower increases in type I & II muscle fiber size, ... but as long as I don't have a study to confirm that, I am hesitant to put too much faith into the (albeit significant) correlations in the West study and would like to refer you to the general scientific consensus that the systemic elevations of purportedly growth promoting hormones in the immediate vicinity of a workout are not a reliable predictor of the exercise induced changes in strength and/or body composition (Schoenfeld. 2013).
  • Ackerman, James, et al. "The effect of an acute antioxidant supplementation compared with placebo on performance and hormonal response during a high volume resistance training session." Journal of the International Society of Sports Nutrition 11.1 (2014): 10.
  • Bentley, David J., et al. "Acute antioxidant supplementation improves endurance performance in trained athletes." Research in Sports Medicine 20.1 (2012): 1-12. 
  • Borg, Gunnar, Peter Hassmén, and Monica Lagerström. "Perceived exertion related to heart rate and blood lactate during arm and leg exercise." European Journal of Applied Physiology and Occupational Physiology 56.6 (1987): 679-685.
  • Mach, John, et al. "The Effect of Antioxidant Supplementation on Fatigue during Exercise: Potential Role for NAD+ (H)." Nutrients 2.3 (2010): 319-329. 
  • Schoenfeld, Brad J. "Postexercise hypertrophic adaptations: a reexamination of the hormone hypothesis and its applicability to resistance training program design." The Journal of Strength & Conditioning Research 27.6 (2013): 1720-1730. 
  • West, Daniel WD, and Stuart M. Phillips. "Associations of exercise-induced hormone profiles and gains in strength and hypertrophy in a large cohort after weight training." European journal of applied physiology 112.7 (2012): 2693-2702.